Subject: Re: LGPL and DLLs
From: Ian Lance Taylor <>
Date: 13 Feb 2005 15:35:50 -0500

Kelly Anderson <> writes:

> If you put the LGPL library code into a DLL, and give instructions on
> how to construct that DLL (or the project already comes in DLL form in
> the first place) then is this generally understood to fulfill the
> re-linking requirements of the LGPL?

Yes, this is the general understanding.

> Assuming that the DLL is a solution to the re-linking issue, is the
> proprietary company then within it's rights to say, "If, however, you
> do replace this DLL with another version, you've gone off the
> reservation, and we can't provide technical support for you until you
> put a 'blessed' version of the DLL back into your installation."

Yes, certainly.  The license imposes no requirements on support.  I
would be shocked if a proprietary company agreed to support a relinked

For that matter, a company can say "If you call us or send us an
e-mail, we will terminate your support contract," and some companies
do appear to operate that way.

> It seems unfair to expect a closed source company to provide support
> for a DLL that has been changed by the end user under an open source
> license. The re-linking clause makes closed source shops nervous about
> using code licensed under the LGPL. (At least that's my personal
> experience.)

In my experience, nobody ever relinks.  It's an understandable fear,
but an empty one.